Preliminary results in our laboratory indicate that prostatic 5 alpha-reductase and arginase activities may be useful tools in selecting agents effective in the chemotherapy of prostatic cancer. These enzyme activities are determined on prostatic tissues of rats following the short-term (4-7 days) or long-term (1/2-3 months) administration of chemotherapeutic agents. The drugs will be given to intact or castrated (mature and immature) rats, dogs and baboons. Only long-term effects will be determined in the latter 2 animals and the study will include, in addition to the enzyme activities, a study of the histology and other biochemical parameters. An in vitro approach by organ culture will also be developed.